The prior art discloses various electromagnetically actuable high-pressure valves having a valve seat which can be closed off by a sealing element and which is arranged between a low-pressure side and a high-pressure side of the valve, wherein the sealing element is arranged so as to be movable between an open position and a closed position, having a movably arranged armature, and having an electrically energizable coil which is designed and arranged so as to be suitable for acting on the armature. Valves of said type are used for example as high-pressure valves for regulating the rail pressure in common rail technology for gasoline direct injection. In this field of use, the high-pressure valve is arranged between a fuel supply line and a high-pressure pump which generates the high pressure, for example 280 bar, prevailing in the rail, and said high-pressure valve regulates the inflow of fuel into the high-pressure pump and the build-up of the pressure in the high-pressure pump, which pressure is then transferred into the rail.
A schematic diagram of the system known from the prior art, and the basic construction of the high-pressure valve used therein, are illustrated in FIG. 5.
FIG. 5 shows a high-pressure valve 1 with a low-pressure side N a high-pressure side H, wherein a valve seat 5 that can be closed off by a sealing element 2 is arranged between the low-pressure side N and the high-pressure side H. The low-pressure side N of the high-pressure valve 1 is connected to an inflow line 6 via which fuel delivered by a low-pressure pump is made available. The high-pressure side H of the high-pressure valve 1 is connected to the cylinder of a high-pressure pump 70, wherein the pressure of the fuel situated in the cylinder is built up, and said fuel is delivered in the direction of the rail 73, by a piston 71 when the valve seat 5 is closed. A check valve 75 is arranged between the rail 73 and the cylinder, which check valve prevents a flow of the high-pressure medium back from the rail 73 into the cylinder volume of the high-pressure pump 70.
According to the prior art, the sealing element 2 of the high-pressure valve 1 is connected via a plunger 8 to an armature and can be moved by electrical energization of a coil 31 which acts on the armature. The high-pressure valve 1 according to the prior art is in the form of a normally-open valve owing to a helical spring 15 arranged in the region of the armature, such that a pressure is built up by the high-pressure pump 70 only when the high-pressure valve 1 is closed, that is to say when the sealing element 2 sealingly closes the valve seat 5 such that the high-pressure medium is delivered not back in the direction of the inflow line 6 but rather, overpowering the check valve 75 which is closed by the high pressure in the rail 73 and by additional spring assistance, into the rail 73.
In the case of the high-pressure valves known from the prior art, it is considered to be disadvantageous that highly precise mounting of the armature, piston and sealing element is required to ensure an adequate sealing action of the high-pressure valve. Such highly precise mountings are cumbersome and thus make the manufacture of the valves more expensive.
It is the object of the present invention to further develop a high-pressure valve known from the prior art and to provide a high-pressure valve with improved characteristics.